Macromolecular Diffraction at the Cornell High Energy Synchrotron Source (MacCHESS) provides a facility for developing new technology and for advancing the research goals of structural biologists as well as the broader biological research community. MacCHESS also has a strong commitment to training future leaders, who will be able to translate advances in synchrotron science and structural biology into valuable biomedical applications. New Technology Research and Development projects (TR&Ds) by MacCHESS scientists will continue to be driven in the coming funding period by fundamentally important questions in biology and biomedicine (i.e., Driving Biomedical Projects or DBPs). The DBPs include investigations aimed at understanding complex membrane receptor-signaling systems, defining the regulation of ion channels in neuronal function, probing the catalytic mechanisms of enzymes playing central roles in key metabolic events, and delineating the complex macromolecular assemblies responsible for gene expression. When de-regulated, these processes can lead to the development of cancer and a number of other diseases. The TR&Ds being proposed to aid investigators in their efforts to address these important questions are: 1) Biological Small Angle X-ray Scattering (BioSAXS). New technology for the application of BioSAXS is being developed in response to increasing demands from the structural biology community to obtain information regarding the global conformational changes within macromolecular complexes (e.g. growth factor receptors, RNA-splicing complexes) and/or the changes in their oligomeric states that occur in solution and have important functional consequences. 2) Pressure Cryocooling. This unique MacCHESS technology offers exciting possibilities for trapping important protein conformational and enzymatic intermediate states that have not been previously solved, as well as facilitating structure determination from difficult crystals. 3) Multiple Small Crystals. Many membrane-associated complexes that are directly involved in hormone and growth factor-signaling events, as well as important neurotransmitter receptors and ion channels, give rise to crystals which are very small or diffract poorly. This project will enhance the ability to gain valuable structural information from such crystals. 4) Dynamics of Macromolecules. The goal is to develop new methods to probe macromolecular motions and time-dependent structural changes, both in crystals and in solution, to shed light on mechanisms of enzyme catalysis and biological signaling events. The expectation is that the structure-function information derived from research at MacCHESS will ultimately highlight novel therapeutic targets and aid in the development of clinical strategies for dealing with disease.